Submission #423006

#	Time	Username	Problem	Language	Result	Execution time	Memory
423006		victoriad	Three Friends (BOI14_friends)	C++14	0 / 100	11 ms	4184 KiB

friends

#include <cmath>
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
using namespace std;
int main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	int n;
	string s;
	cin>>n>>s;
	if(n%2==0){
		cout<<"NOT POSSIBLE";
	}
	else{
		int l=0;
		int us=-1;
		vector<char> a;
		int x,y;
		for(int i=0;i<n/2;i++){
			if(s[i]==s[i+n/2]||s[i]==s[i+n/2+1]){
				a.push_back(s[i]);
			}
			else{
				if(l==0){
					l=1;
				}
				else{
					l++;
					cout<<"NOT POSSIBLE";
					break;
				}
			}
		}
		if(l<=1){
		if(s[n/2]!=s[0] && s[n/2]==s[n-1])a.push_back(s[n/2]);
		int y=-1;
		if(l==0){
			for(int i=n/2;i<n-1;i++){
				if(s[i]==s[i+1]){
					y=0;
					break;
				}
			}
			if(s[0]==s[n-1]&& s[0]==s[n/2])y=0;
		}
		else{
			for(int i=0;i<n/2;i++){
				if(s[i]==s[i+1]){
					y=0;
					break;
				}
			}
		}
		if((s[n/2]==s[0] && s[n/2]==s[n/2+1]&& s[n/2]!=s[n-1] && l==0)||y==0){
			cout<<"NOT UNIQUE";
		}
		else if(a.size()!=n/2){
			cout<<"NOT POSSIBLE";
		}
		else{
			for(int i=0;i<a.size();i++){
				cout<<a[i];
			}
		}
		}
	}
	return 0;
}

Compilation message (stderr)

friends.cpp: In function 'int main()':
friends.cpp:60:19: warning: comparison of integer expressions of different signedness: 'std::vector<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   60 |   else if(a.size()!=n/2){
      |           ~~~~~~~~^~~~~
friends.cpp:64:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |    for(int i=0;i<a.size();i++){
      |                ~^~~~~~~~~
friends.cpp:19:7: warning: unused variable 'us' [-Wunused-variable]
   19 |   int us=-1;
      |       ^~
friends.cpp:21:7: warning: unused variable 'x' [-Wunused-variable]
   21 |   int x,y;
      |       ^
friends.cpp:21:9: warning: unused variable 'y' [-Wunused-variable]
   21 |   int x,y;
      |         ^

• Subtask 1: 0 / 35
• Subtask 2: 0 / 65